Engineering Contracts And Specifications

SPECIFICATIONS FOR BOILERS.
for in the specifications, and shall in each case fully stand the specified tests.
21. All plates in the boilers to be made of Steel Plat steel.
The steel plates used in these boilers must be stamped with the maker's name and the tensile strength; to be homogeneous and of uniform quality, to have a tensile strength of not less than 55,000 pounds, nor more than 62,0,00 pounds per square inch, an elastic limit of at least 30,000 pounds per square inch, and an elongation of at least twenty-four (24) per cent, in eight inches.,
Specimens must stand the following bending test, viz.:
To bend double, closing up completely without •showing sign of fracture when bent cold, or after having been heated to a cherry red and plunged into water at 70 degrees Fahrenheit.
The water commissioner shall have the right to order test specimens 2x14 inches, to be cut out of any of the plates to be used in the boilers.
22. All wrought iron for bolts, nuts or other wrought i purposes shall be double refined, and have an ultimate tensile strength of at least 52,000 pounds per square inch, an elastic limit of 26,000 pounds per square inch, and an elongation of eighteen (18) per
cent, in eight inches.
23. Rivets to be Burden's best, and must be capable of bending cold until the sides are in close contact, without sign of fracture; and iron used for screw stays, stay bolts and braces to be of best quality of American manufacture.
24. Tubes to be lap-welded of the best quality Tubes, of American manufacture, of a diameter of 3% inches or 4 inches, and must stand a satisfactory hammer test.
25. All castings shall be free from blow holes, CastlnK*-flaws, scabs, and defects of any description, and
shall be smooth, close-grained, sound, tough, and of true forms and dimensions.
Great care must be taken to make all castings, as nearly as practicable, of uniform thickness throughout, when not otherwise required.
26. All cast iron used under steam pressure Iron c **« shall be of good quality, tough and of even grain,
and shall possess a tensile strength of not less than 22,000 pounds per square inch.